1. Field of the Invention
The invention relates to a method of separating bacteria from a liquid and to a method for culturing the bacteria to produce a polymer useful in liquid clarification and soil conditioning. The invention further relates to the polymeric substance produced and to methods of using the polymeric substance.
2. Description of the Prior Art
Industries which use large amounts of water or other liquids have in many cases been confronted with the problem of purifying these liquids of suspended particulate matter. Where time is not a critical factor, these undesirable particulates may settle out by themselves to the bottom of a container holding the liquid. However, in many cases the particulate matter will not settle out, even after long periods of time.
One of the best solutions to this problem in the past has been the addition of various inorganic chemical flocculants which cause the particulates to adhere to one another and to settle out. The problem with suspended particles is that they are in a colloidal suspension, in which the particles usually have a negative electrical charge. Hence, these particles repel one another and do not coalesce readily to form particles which are sufficiently large to precipitate. The flocculation process involves the neutralization of the charge on the particles. However, neutralization is only the first step. Stirring of the water causes collisions of the small neutralized particles, and forms a so-called "microfloc". Further growth of particles then occurs to form particles of sufficient size to settle rapidly in a sedimentation basin.
In the past, the most widely used flocculating agents have been various ferric salts and alum. More recently, various types of organic polymers have gained wide acceptance as flocculants. Though somewhat more expensive than the traditional inorganic flocculants, the greater effectiveness of organic polymers usually more than offsets the price differential. Furthermore, the older method of using inorganic polymers required relatively large amounts of inorganic salts. This practice added not only to the costs of the chemicals but also to the costs associated with the handling and the disposal of large volumes of sludge.
The above-mentioned polymeric materials do not occur naturally, thus, potential users must purchase the materials, at considerable cost, from various chemical manufacturers.
It would, therefore, be desirable to use as flocculants polymer materials which could be readily and inexpensively produced or secured.